Motor drive units (MDUs) are often employed with a variety of surgical tools via a connection interface for imparting a rotation to a blade or ablation tool for engagement with a surgical site, typically for resection or the manipulating and removal of tissue. Often the tool employs a cannulated shaft or other passage for providing suction to the surgical site for evacuation of surgical material. In conventional approaches, the connection interface is typically in contact with fluid from the surgical site via a suction path. Surgically contaminated instruments must either be disposed of or sterilized in an autoclave to counter the risk of infection. Moreover, the contact with the fluid and the exposure to autoclaving for sterilization presents a problem with possible leakage into the motor chamber, which should remain dry to promote longevity of the motor powering the drive unit.